Abstract

Two strains, NCCP-650T and NCCP-667, were isolated from industrial effluent and their taxonomic positions were investigated using a polyphasic taxonomic approach. The strains were found to be Gram-stain negative, strictly aerobic, motile short rods, which are tolerant to heavy-metals (Cr+2, As+2, Pb+2 and Cu+2). Cells were observed to grow at a temperature range of 10–37 °C (optimal 25–33 °C), pH range of 5.5–10.0 (optimal 6.5–7.5) and can tolerate 0–7 % NaCl (w/v) (optimum 0–1 %) in tryptic soya agar medium. Sequencing of the 16S rRNA gene and two housekeeping genes, gyrB and nirK, of the isolated strains revealed that both strains belong to the Betaproteobacteria showing highest sequence similarities with members of the genus Alcaligenes. The chemotaxonomic data [major quinones as Q-8; predominant cellular fatty acids as summed features 3 (C16 :1 ω7c/iso-C15 :0 2OH) and C16:0 followed by Summed features 2 (iso-C16 :1 I/C14 :0 3OH), C17:0 Cyclo and C18:1 ω7c; major polar lipids as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid] also supported the affiliation of the isolated strains with the genus Alcaligenes. DNA–DNA hybridizations between the two strains and with closely related type strains of species of the genus Alcaligenes confirmed that both isolates belong to a single novel species within the genus Alcaligenes. On the basis of phylogenetic analyses, physiological, biochemical characteristics and DNA–DNA hybridization, the isolated strains can be differentiated from established Alcaligenes species and thus represent a novel species, for which the name Alcaligenes pakistanensis sp. nov. is proposed with the type strain NCCP-650T (=LMG 28368T = KCTC42083T = JCM 30216T).

Notes

Acknowledgments

The financial support from Higher Education Commission of Pakistan to S.A. under International Research Support Initiative Program (IRSIP) is gratefully acknowledged. This work was also supported partly by financial assistance from PSDP funded Project Research for Agricultural Development Project (RADP) under a sub-project (Grant No. CS-55/RADP/PARC) entitled “Establishment of Microbial Bio-Resource Laboratories: National Culture Collection of Pakistan (NCCP)” from Pakistan Agricultural Research Council (PARC), Islamabad, Pakistan and partially from Japan Society for Promotion of Science (JSPS) under fellowship program to I.A.